Thread-pull-off device for buttonhole machines



A. L.,PLAMONDON. THREAD PULL-OFF DEVICE FOR BUTTONHOLE MACHINES.

I APPLICATION FILED SEPT. 14, I920.

Patented June 27,1922.

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Evan?? mon use. More particularly movement, so that UNITE THBEAD-PULL-O'FF DEVICE Application filed September 1 T 0 all whom it may Be it known that concern:

1, ART-nun L. PLAMON- DON, a citizen of the United States, and resident of Dorchester, Boston, county of Suti'olk, Commonwealth of Massachusetts, have invented an improvement in Thread-Pull- Oti Devices for Buttonhole Machines, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts in each of the several views.

This invention relates to buttonhole machines of the lock-stitch type, and while not limited thereto, is well adapted for use with the Singer lock-stitch machine, now in comthe invention relates to an improvement in the tread pulloff device which is employed in the type of machine stated to pull from the bobbin a requisite length of thread for co-operation with the loop of the needle thread in starting the buttonhole. Thread pull-off devices for this purpose have hitherto consisted in a swinging finger, actuated by the cutting-off slide and having always the same range of it has not been possible to vary the amount of thread pulled off to take care of different conditions as to character of the material etc. In working on heavier materials, however, it is not necessary to pull off so much thread to start the buttonhole since the loop formed as the needle backs out of the cloth, is held straight open better with heavier cloth having more body, while with lighter cloth or material, the loop is more unsteady and is apt to be thrown to one side or the other, thereby rendering uncertain the catch of the bobbin thread at the beginning of the operation. The principal object of the present invention is to provide means whereby the amount of thread pulled off from the bobbin case to act in co-operation with the needle loop may be varied as required, permitting the pulling off of more thread when required, as with lighter materials so that the catching of the thread is insured at the start, and notwithstanding any irregularity in the position of the loop, terials only enough thread need be pulled off to insure the catching of the thread, the loop being in this case more steadily held. Further it has hitherto been common practice to slacken the tension of the needle thread with lighter materials so as to insure Specification-of Letters iPa-tent.

while with heavier mavjust below FOR BUTTONHOLE l 4., 1920. Serial Nomi-10,093,

the catching bin, which has resulted in a more poorly made and inferior appearing buttonhole. The present device is therefore adapted to improve the appearance and character of the buttonhole, by permitting a continuous even tension on the needle thread since with more thread pulled off it is insured that the lock-stitch will be obta-ined' at the-very beginning of every operation." The foregoing' and other the invention will more fully appear-from the following detailed description, and the distinctive features of novelty will be pointed out in the appended claims.

Referring to the drawings:

Figure 1 is a par-t'al bottom plan view showing the thread pull-off finger "of my invention with the raceway and .shuttle -co-' operative therewith;

Figure ,2'is a partial from the left in Figure ing shown in section I Figure 3 is a plan view showing the adjusiable finger of my invention detached; an

Figure 4: is anedge view of the fingerof Figure 3. K 1

10 indicates a portion" of the machine frame with a usual rock shaft 11 horizon tally journalled therein having at its end an arm 12 bearing a yoke 13, which actuates the oscillatory shuttle 14. 15 indicates the raceway in which the shuttle operates, and 16 denotes the bobbin stationarily mounted for oscillation of the shuttle therearound,

end view looking 1, certain parts hethe bobbin having a thread guide 17 extend-.

ing upward therefrom and co-operating with the point 14? of the shuttle. 18 denotes a slide mounted for horizontal transverse movement in the frame and actuated by a lever 19 pivoted to the frame at 20. This slide has secured at its end, a cutting-0E knife 21 which severs the thread. The slide 18 also has fixed thereto a pin 22 which operates the thread of the parts so far pull-off finger 23, are, or may be of usual construction and as exhibited in the well known Singer buttonhole machine. The finger 23 is pivoted at 24 to the frame, and is equipped with an operative extremity 23 adapted to catch the bobbin thread as usual the needle hole 25, to pull requisite quantity of thread for co-operation with the loop. In accordance with my inoff the Ratented June 2'7, 1922.:

of the short end from the bobobjects and-advantages of E I pull-off finger 23. All mentioned except the vention the range of movement of this pulloif finger may be varied and changed it will engage the thread earlier or later in the operation according to the amount of thread it is desired to pull. off. This varying or shifting of the range of movement of the finger 23 may be accomplished in different ways, but herein for illustrative purposes I show the finger at its portion where it is engaged by the pin 22, formed with a relatively large opening 26. Over this opening I fix adjustably a plate 27 bearing an elongated slot 28 of a width to fit the pin 22 and in which said pin operates. This plate 27 is adjustably secured to the finger by means of screws 29 which pass through slots 30 of the plate elongated somewhat transversely, so that the plate 27 may be slid and adjusted with reference to the finger, thus positioning the pin receiving slot 28 in different positions with reference to the finger, and hence causing the finger to occupy different positions with a given position of the pin 22 and the slide 18. Thus the finger is caused to engage the thread sooner and to move farther in engagement therewith, drawing out more thread, or when differently set, engaging the thread. later and hence drawing out a shorter length, as may be required. I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing de scription to indicate the scope of the inven tion.

maving described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The combination with the bobbin and shuttle of a lock stitch. buttonhole machine, of a finger mounted for oscillation to engage the bobbin thread for pulling off the same, and a thread cutting-off slide, said finger and slide equipped with co-operative means for engagement of the finger by the slide and for varying the relation of the finger to the slide whereby the finger is operated by the slide and the limits of movement of the finger may be changed at will, for the purpose stated.

2. The combination with the stitch forming instrumentalities of a lock stitch buttonhole machine, of a finger mounted for oscillation to engage the bobbin thread for pull mg off the same, a thread cutting off slide bearing a pin engaging said finger, and means for varying the relation of said finger to said slide for changing the limits of movement of the finger for the purpose stated.

3. The combination with the stitch forming instrumentalities of a lock stitch button hole machine, of a. finger mounted for oscillation to engage the bobbin thread for pull ing off the same, a plate adjustably mounted on said finger with a slot therein and a thread cutting off. slide bearing a pin engaging said slot, the adjustment of said plate on said finger changing the relation of said finger to said slide for the purpose stated.

In testimony whereof I have signed my name to this specification.

ARTHUR L. PLAMONDON. 

